DE3039483C2 - Incremental length or angle measuring device - Google Patents

Abstract

A position measuring instrument of the type having a scale and a scanning unit is provided with a plurality of reference marks on the scale. An identification mark is associated with each reference mark, and each identification mark is uniquely coded. The scanning unit operates to read the identification marks and to generate identification signals which are applied to a comparator or to a computer. The comparator or computer compares the identification signal corresponding to each reference mark with a set of designation signals. Only if a correspondence is found between the identification signal and one of the designation signals is the reference mark allowed to go into operation. Thus, by merely changing the designation signals electronically, any desired subset of a total number of reference marks can be enabled. The selected reference marks can readily be changed electronically without physical manipulation of the measuring instrument.

Description

a) a scanning device (A) for the identification features (C \ ... n) is connected to a comparison element (V, R) , in which each of the identification features (C \ ... b) is scanned at the associated reference mark ( Ni ... ") obtained location information km is fed in;

b) the comparison element (V. R) is connected to a data memory (S, S ') from which the previously selected, the respective identification features (Q ... ") of the associated reference mark to be selected (Ni ...") corresponding, Reference mark-specific information is fed into the comparison element (V, R);

c) the comparison element (V, R) is connected to a logic circuit (U, U ') into which the comparison result and each pulse (Rs) obtained by scanning a reference mark (Ni ... ") is fed;

d) the logic circuit (U, U ') is connected to an evaluation device (Z) into which a reference pulse (Rj) is fed for control purposes as a function of the logic conditions

2. Measuring device according to claim 1, characterized in that a digital computer (R) is provided as a comparison element, which has access to an electronic data memory (S) for information that corresponds to the identification features of the associated reference marks (N \ ... ") Furthermore, a selection device (T) for selecting reference marks (N \ ... ") is connected to the digital computer (R) , with the aid of which information specific to reference marks can be stored in the data memory (SJ)

3. Measuring device according to claim 1, characterized in that a comparator (V) as a comparison element via a data memory (S ') is connected to a selection device (Na) which carries out a coincidence check between the identification features (Q ... C _n ) makes reference mark-specific information obtained and the information pending in the data memory (S ') by means of the selection device (Na)

4. Measuring device according to claim 1 to 3, characterized in that the reference marks (N \ .. ") coded graduation fields are assigned as identification features (C \ .. n).

5. Measuring device according to claim 4, characterized in that the identification features (C _n ) are additionally attached in decimal digits (1,2,3,4) in the vicinity of the reference marks (N \ .. ") and on the selection device (T, Na) are.

6. Measuring device according to claim 4, characterized in that the identification features (Ci .. a) are derived from the position of the reference marks (Ni .. ") to the zero point of the measuring device, and these positions also as decimal numbers near the reference marks (N _t .. ") and are attached to the selection device (T, Na) .

7. Measuring device according to claim 4, characterized in that the identification features (C \ .. A) are also attached as color markings in the vicinity of the reference marks (Ni .. _tt ) and on the selection device (T, Na).

8. Measuring device according to claim 3, characterized in that the memory (S ') and the selection device (Na) are realized by a coding switch.

9. Measuring device according to claim 2, characterized in that the digital computer (R) is a microcomputer

The invention relates to an incremental land

Gen or angle measuring device according to the features of the preamble of claim 1.

In DE-AS 25 40412 it is described that along an incremental graduation a number of reference marks are attached to each other at fixed intervals With switching means (for example magnets) arranged on the scale or in its immediate vicinity and reed switches) one or more can be selected from the series of reference marks and used to be brought. To do this, according to this pressure Font the intended identification features Magnets are moved along the incremental graduation to the selected reference mark respectively assign a magnet. With deA this way selected reference marks can use the different the most important control processes are triggered in the meter.

Furthermore, devices for evaluating all coded reference marks assigned to fixed positions are known and described e.g. in DE-PS 24 16 212 and DE-OS 24 18 909. These positions are imprinted on the reference marks in encrypted form as identification features so that during the Measuring process the reference marks are queried, and the counter reading for each of the reference marks ge if necessary on the numerical value of the respective Re position belonging to the reference mark.

The invention is based on the object of further improving a device for selecting reference marks in incremental measuring devices, and make the selection of reference marks easier and safer.

According to the invention, this object is achieved by the characterizing features of claim 1 The advantages of the invention are substantial in that the selection of the reference marks can be made from the control panel, and none mechanical manipulations must be carried out on the transducer. The required identification features (code tracks) can be easily identified Apply effort already in the production of the graduation on the measuring standard. Since in today's measuring devices the evaluation device is generally already equipped with a microcomputer, memory and control panel.

3 4

is permitted, require the required according to the invention. The digital computer R is programmed to each

Similar electronic components also hardly by scanning the identification features Q .. <

Extra effort. information obtained with the memory content

As a result of the configuration of the device according to FIG. 1, only the information in the data memory S is the same

Further advantages result from subclaims. 5 of the selected reference marks N ₁ .. 4 or their

Based on the drawings, the invention should also be able to contain identification features G .. 4

are explained here. It only shows this information from the data memory 5

F i g. 1 is a schematic representation of a measurement query. Results this examination for equality

direction, a positive result, the digital computer R delivers

Fig. 2 shows a further schematic representation of a 10 a signal that is input into an electronic unit t /

Measuring device, ^ is fed.

Fig. 3 the top view of a measuring standard and the electronic component i / can be a logical one

the scanning field of a scanning device. Logic circuit e.g. be an AND gate, so that

In Fig. 1 shows that a material measure delivers only one reference pulse Rj to the evaluation device A / device Z , which is permanently attached to the bed W1 of a machine tool, when a signal is present at its two inputs at the carriage W _{2 of the machine tool}

The ordered scanning device A moves at a relative position. The reference pulse Rj only comes into effect,

movements of bed Wi and carriage W ₂ along the if by scanning the reference mark M - · 4 a

Measuring standard M and probes the pulse generated on it, and by comparing information

th markings. These markings and the portions from scanned identifications are Q. 4

feeler device A are shown in FIG. 3 unspecified With T 'and stored information, a signal PY ER-

is the grid division of the incremental measuring device is generated, and both the pulse Rj and the signal

denotes the anlie- in known manner by the Abtastern- PY simultaneously on the electronic component U

direction A is read by means of scanning field Ar The gen.

Scanning field Ar consists of two sub-fields, which are opposite to each other. Way can be set by simple actuation

The selection keyboard Tbefiebige reference marks Ni are offset from one another by V _{4 of} the graduation period. . 4th

by selecting two from the series of reference marks when reading the division,

90 ° phase-shifted scanning generated, the It is obvious to a person skilled in the art that he

the direction detection of the relative movement of the invention can also be designed so that reference im-

allow mutually movable components Wi and W _2. 30 pulses only come into effect if an information

In addition to the incremental graduation T, there is a relatively simple inequality on the comparison

Material measure M a number of reference marks measure is useful, for example, when off

N \, Ni, M, M, whose distances from one another set a number of reference marks very many selected

Each of these reference marks is intended to be co-ordinated with special. In this case the information

serve marks C \, Ci, C _3, Ca (provided in the off 3s stored in the data memory S, the identifi- the

example encodes the numbers 1, 2, 3 and 4), the decorative features of the unwanted reference

identify the respective reference mark N \ .. 4. In the brands correspond. Only if the above

Scanning device A are next to the scanning field Ar for information comparison equality results, the R ^ fe-

the division r'roch scanning fields An and Ac provided, the reference pulse suppressed, in the event of inequality, the

each of the reference mark track or the identification 40 reference pulses for effect,

Scan the feature track. Another facility for carrying out the inven-

In the case of relative movements between the mechanical engineering method with a similar basic structure

divide Wi and W ₂ are in the scanner A is in FIG. 2 described.

Measurement signals generated which are fed to a pulse shaper stage / while the reference mark is being passed. The pulses control the forward 45 Ni .. 4 from the scanning field Ac in each case the down counter Z , which indicates the position of the identification part W) assigned to a construction reference mark Ni .. 4 in relation to the second component W ₂ Characteristic C \ .. 4 scanned and the resulting information each time a reference mark Ni .. 4 is passed over - for example in the form of a combination, a reference simulation of binary signals is also detected in the scanning device A - in a comparator V one- pulse Rs , a further pulse shaper stage Jn 50 fed

and from there <m the input of an elec- At further inputs of the! Comparator V is a

tronic unit i / laid electronic memory S (e.g. RAM) connected,

While the reference marks are being passed over, all identifying features of the

N] .. 4 is the reference mark Ni .. 4 from the scanning field / Ic as a combination of binary

Reference mark Ni .. 4 associated identification feature 55 contains stored signals to this memory 5 is

Ci .. 4 scanned and the information obtained therefrom connected to a selection device Na , with the one

a processing stage Jc then fed to or several reference marks Ni .. 4 for evaluation

this information in the form of data will be selectable in one. The selection device

Digital computer R read in. An input module in Na can be a rotary switch or a keyboard. Will

In the form of a keyboard T acts on the digital computer R 60 as a selection device Mt a special coding switch

a. Used in conjunction with the digital computer R , the electronic memory S can be omitted.

can use the keyboard T information in the form of len, since the coding of the identifying features

Data entered into an electronic data memory 5- Q .. 4 and the code of the coding switch match.

be saved. This information to be stored.

ons correspond to the information content of identifications, for example the reference mark H ₃ selected

Zierungsmerkmalen C \ .. "of those reference marks are, then the identifiers are from the memory 5

Ni .. 4. the information for the reference mark N ₃ from the series of reference marks Ni .. 4 read out

should be selected. and fed into the comparator V in binary form

5

If the scanning device A is now moved along the incremental graduation T , a pulse & is generated when the reference mark / V _{3 is passed and in the}

above-described way to an input of the logi ι

see link U placed. At the same time who which the coded identification features are scanned and the combination of binary signals corresponding to the code is fed into the comparator V via a second input. The comparator V compares the signal combination and, if they are equal, delivers a pulse Vj to the second input of the logic element.

Only when a pulse Rs is applied at the same time

from the reference mark N3 and a pulse V) to i

due to the confirmation of identity of the identification 15 '

characteristics from read and stored code '.

a reference pulse Rj comes from the linkage f '

güed U to the A >>? value facility Z and can there jj

trigger any control commands, for example the pre <

Set the downward counter (Z) to the value »zero«. 20; ']

When crossing over other than the selected reference j

The comparator V cannot limit a pulse V ₁

deliver, since the coincidence of read and from "!

the memory S read out identification features is not given

A particularly simple and reliable selection of a reference mark N \. . 4 from the series of reference marks can be done with the devices described above if the approximate position of a reference mark M on the bed W _{x of the machine tool.} · 4 marked and the respective reference mark N \ .. 4

is figured speaking. At the bed W \ the tool measure- ί

The corresponding digits 1, 2, 3 and 4 are attached here to the corresponding code information, which the operator can still see from a greater distance. In the same way, numbers 1, 2, 3, 4, etc. are attached to the selection device Γ or Na

The identification of the reference marks can of course also be done by attaching position

honors take place. So z. B. the reference mark;

ke that is attached 300 mm from the zero point of the measuring device has the marking "300", in accordance with the marking on the selection device T or N _A. The corresponding encoded TEI 45 \ lung field at the reference mark in this case contains useful encrypts the number "300".

It is also possible to use color markings in pairs.

The display def identification of the reference marks can also be done by alphanumeric displays in the Evaluation device time sequences.

It is advisable to accommodate the devices described above in a housing G on the control panel of the machine, so that the operation of the selection device is possible in a comfortable manner for the operator. The control panel can also be part of a numerical control.

For this purpose 2 sheets of drawings

65

Claims (1)

Patent claims: * 1. Incremental length or angle measuring device with an arrangement for selecting reference marks from a large number of reference marks, which are arranged along a grid division in which reference marks can be identified by position information of scannable features, characterized by the combination of the following Characteristics: